The present disclosure relates generally to utilizing ICMP (Internet Control Message Protocol) to obtain network routing information.
Route tracing is used in communication networks to identify problem areas and provide detailed information about the network. Traceroute is an example of a tool that is used to trace the route of a packet over each hop from a client to a remote host by reporting all router addresses therebetween. Traceroute is widely used in IP networks for troubleshooting and status verification purposes. The traceroute program sends a series of trace packets (probe packets) to an IP address and awaits an ICMP reply. ICMP is described in RFC 792, “Internet Control Message Protocol”, DARPA Internet Program Protocol Specification, J. Postel, September 1981, which is incorporated herein by reference in its entirety.
Conventional implementation of traceroute uses only the IP address of an inbound interface or router ID address information attached inside the ICMP packets, and does not provide routing instance information. When using a traceroute tool, it is not obvious where the routing domain boundary is if the interface address is not in a global DNS (Domain Name System) table. This is also the case when the link uses private IP address space. Routing information may be obtained through IGP (Interior Gateway Protocol), however, with increasing demand on QoS (Quality of Service) routing, and with IETF effort on Multi-Topology for IS-IS (Intermediate System to Intermediate System) and OSPF (Open Shortest Path First), IGP troubleshooting has become difficult. Furthermore, methods currently available for discovering routing instance information require access to databases which may not be up to date, may be difficult to access, or require authorization to access information due to security issues. Routing instance information is important for use by network operators in troubleshooting without access to a full local routing database.
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